Ice making machine
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention generally relates to an ice making machine and particularly to an ice maker of such a type in which an ice making machinery section thereof is disposed on an ice storage section in which ice produced by the ice making machinery section is stored. 
     2. Prior Art 
     In the hitherto known ice making machine of the above-mentioned type, as illustrated in FIG. 3 of the accompanying drawings, the upper machinery section includes a bottom plate 6, which is provided underneath a platform or base plate 5 and serves as the ceiling wall of the ice storage bin of the lower ice storage section. The base plate 5 is adapted to support the ice making mechanical elements including a refrigeration system (not shown). By the provision of such a dual-plate structure, both heat insulation of the ice storage bin and prevention of dust deposition therein can be realized. An ice discharge chute 3 which is a member in the upper machinery section is fitted into an opening 5b formed in the base plate 5 and an opening 6b of the bottom plate 6, wherein the ice discharge chute 3 is supported on the base plate 5 at a radially enlarged bulge portion 3d of the chute 3 by simply disposing it on the base plate 5 or by bonding. A gasket 7 is mounted around the opening 6b of the bottom plate 6 for hermetically closing a gap which would otherwise appear between the outer cylindrical surface 3c of the lower end portion 3b of the ice discharge chute 3 and the opening 6b of the bottom plate 6, in order to prevent leakage of cool air from and invasion of dust into the ice storage bin. 
     In the above machine, the opening 6b formed in the bottom plate 6 and the bottom end of the ice discharge chute 3 are positioned on the same plane in a state ready for the ice making operation after assembly. As a result, although a major portion of water droplets produced within the ice discharge chute 3 due to melting of ice particles or for other reasons drops through the bottom end 3b of the ice discharge pipe 3 into the ice storage bin, the remaining part of the water droplets may move along the lower surface 6a of the bottom plate 6, i.e. the ceiling wall of the ice storage bin after crossing the gasket 7 (refer to an arrow 11 in FIG. 3). When the droplets on the ceiling wall of the ice storage bin evaporate, traces are formed on the ceiling wall due to deposition of impurities contained in the water droplets, which are unsanitary in appearance. It should be noted that ice formed of water containing a greater amount of impurities is inherently easier to melt. 
     The above disadvantage can certainly be eliminated by extending the ice discharge chute 3 to such an extent that the bottom end 3b thereof projects below the bottom plate 6 to thereby prevent the water droplets from migrating or propagating onto the lower surface 6a of the bottom plate 6. In that case, however, a downwardly projecting portion is formed on the lower surface of the bottom plate 6 of the machinery section. It is to be noted that for an ice making machine having an ice making machinery section disposed on the ice storage section, the ice making machinery section incorporating therein the ice discharge chute 3 is commonly packed separately from the ice storage section for convenience during transportation to a required location. Thus, the presence of the downwardly projecting portion makes the packing of the ice making machinery section troublesome. Further, precautions must be taken so that the projecting portion is not damaged during transportation, which is clearly undesirable. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide an ice making machine in which the droplets resulting from melting of ice are positively prevented from moving onto the lower surface of the bottom plate and which has no projections protruding from the bottom plate which provide obstacles to the packing and transportation of the ice making machinery section having assembled therein the ice discharge chute. 
     With the above object in view, the invention provides an ice making machine which comprises an ice storage section disposed at a lower position, and an ice making machinery section including a bottom plate having an opening formed therein, the machinery section being positioned above the ice storage section with the bottom plate thereof disposed on the ice storage section. The ice making machinery section further includes ice discharge means, and an ice discharge chute having an upper end portion communicated with the ice discharge means and a lower end portion communicated through the opening in the bottom plate with the interior of the ice storage section. The bottom plate has an upwardly concaved portion, in which the opening is formed, to define a recess. The lower end portion of the ice discharge chute extends downwardly into the recess through the opening only to such an extent that the bottom end of the lower end portion thereof does not project downwardly beyond the lower surface of the bottom plate. 
     By virtue of the provision of the upwardly concaved recess in the bottom plate of the ice making machinery section so as to allow the ice discharging chute to extend through the opening formed in the concaved bottom plate portion, the water droplets resulting from the melting of ice within the ice discharge chute are positively prevented from moving or propagating onto the lower surface of the bottom wall, whereby all he droplets are forced to drop into the ice storage section from the bottom end of the ice discharge chute, leaving no traces of evaporization on the lower surface of the bottom plate (i.e. the ceiling wall of the ice storage section). 
     Further, as the depth to which the ice discharging pipe is allowed to extend into and through the recess is so selected as to be smaller than the depth of the recess, no obstacles resulting from the projection will be encountered in the packing and transportation of the ice making machinery section having assembled therein the ice discharge chute. This significantly facilitates the packing and transportation. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A more detailed understanding of the present invention may be had from the following description of a preferred embodiment thereof, given by way of example, and to be read and understood in conjunction with the accompanying drawings, in which: 
     FIG. 1 is a sectional view generally showing a whole structure of an ice making machine according to a preferred embodiment of the invention; 
     FIG. 2 is an enlarged sectional view of a major portion of the ice making machine shown in FIG. 1; and 
     FIG. 3 is an enlarged sectional view of a major portion of a conventional ice making machine. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the drawings, particularly to FIG. 1, there is shown an ice making machine 10 constructed according to the preferred embodiment of the invention and comprising an upper ice making machinery section 10a disposed on a lower ice storage section 10b. The machinery section 10a includes a housing 10c in which a refrigeration casing 1, constituting an auger type ice making unit, is housed together with a known refrigeration system (not shown) such as a compressor, an evaporator, and others, as well as various structural and electrical parts. An ice discharging port 2 is communicated with the refrigeration casing 1 at a top end thereof and adapted to receive the ice produced within the refrigeration casing 1. An ice discharge chute 3 has a top end portion connected to the ice discharge port 2 and a bottom end portion 3b opened into an ice storage bin or chamber 4 of the ice storage section 10b. A heat insulation wall 4a defines the ice storage chamber 4 in cooperation with a bottom plate 6 of the upper ice making machinery section 10a. Thus, it will be noted that the bottom plate 6 also constitutes a ceiling wall of the ice storage chamber 4 when the ice making machinery section 10a is disposed on the ice storage section 10b. The bottom plate 6 is connected to a side wall 5a having a substantially L-shaped cross-section and extending vertically downwardly from the peripheral edge of a platform or base plate 5 adapted to support the refrigeration system and others. The housing 10c of the ice making machinery section has a bottom peripheral edge thereof secured to the base plate 5. 
     The refrigeration system within the ice making machinery section 10a including the refrigerator casing 1 is disposed on the base plate 5 and supported through the bottom plate 6 provided underneath the base plate 5 by the heat insulation wall 4a of the ice storage section 10b. Ice produced within the refrigerator casing 1 in a manner well known in the art is discharged into the ice storage chamber 4 by way of the discharge port 2 and the ice discharge chute 3. 
     In the auger type ice making unit, raw water to be iced is supplied into a refrigerating casing having an outer peripheral surface which is wound with a cooling tube, while a screw blade assembly disposed within the refrigerator casin is rotated to scrape off ice layers formed on the inner circumferential surface of the refrigerator casing, the semisolid ice layers removed therefrom being transported upwardly to the ice discharge port, as well known in the art. Differences exist in the freezing points between pure water and the impurities contained therein, and pure water tends to ice first. Consequently, as the ice making operation is continued, the impurities concentration of the raw water contained within the refrigerator casing increases progressively, ultimately resulting in that ice is made from raw water having a high impurities concentration. On the other hand, the melting points of the impurities are higher than that of the pure water. Accordingly, the ice containing impurities is likely to melt earlier than ice made from substantially pure water alone. Thus, the ice containing impurities may already melt within the ice discharge chute 3, resulting in spattered water particles depositing on the inner cylindrical surface 3a thereof to grow into water droplets. 
     The water droplets flow down under gravity along the inner cylindrical surface 3a of the ice discharge chute 3 and drop into the ice storage chamber 4 from the lower end portion 3b of the ice discharge pipe 3. Although some portion of the water droplets that have dropped within the ice storage chamber 4 may remain deposited on ice chips (not shown) within the chamber 4, a major portion of the water droplets is discharged outwardly through a drain opening (not shown) formed in the bottom of the ice storage chamber 4. 
     Now, description will be made in further detail by reference to FIG. 2. The ice discharge chute 3 is disposed and supported on a surface region of the base plate 5 located around and in the vicinity of the opening 5b which is formed in the base plate 5 with the aid of a hood- or funnel-like enlarged portion 3d formed above and close to the lower end portion 3b of the chute 3, wherein a gap formed between the outer peripheral surface 3c of the lower end portion 3b of the ice discharge chute 3 and the peripheral wall of the opening 6b formed in the bottom plate 6 is hermetically closed or sealed by a gasket 7 mounted on the bottom plate 6. More specifically, the portion of the bottom plate 6 which defines and surrounds opening 6b therein is in the form of a recess 8, into which the lower end portion 3b of the ice discharge chute 3 extends. The recess portion 8 is formed simultaneously with the formation of the opening 6b by punching so that the depth L of the recess 8 from the reference plane or the lower surface 6a of the bottom plate 6 is slightly greater than the length h of the lower end portion 3b extending into the recess 8. Thus, the bottom end of the lower end portion 3b cannot project downwardly beyond the reference plane (i.e. lower surface 6a). The length h by which the lower end portion 3b of the ice discharge chute 3 extends downwardly from the opening 6b into the recess 8 may preferably be 2 to 3 mm or more so that the water droplets flowing down over and along the inner circumferential surface 3a of the ice discharge chute 3 can be positively prevented from creeping onto the outer circumferential surface 3c around the bottom peripheral edge of the lower end portion 3b of the ice discharge chute 3. With this structure, the water droplets flowing downwardly under gravity over and along the inner circumferential surface 3a of the ice discharge chute 3 are forced to drop into the ice storage chamber 4 as indicated by an arrow 11. 
     It will be appreciated from the above description that the water droplets are positively prevented from propagating or migrating onto the lower surface 6a of the bottom plate 6 and therefore no trace of deposition of the impurities due to evaporization of the water droplets can be formed on the lower surface 6a of the bottom plate 6. Further, since the length h which the lower end portion 3b of the ice discharge chute 3 extends downwardly in the recess 8 is shorter than the depth L of the recess 8, there is no projection extending downwardly beyond the lower surface of the bottom plate 6 of the ice making machinery section 10a, even when the later is assembled integrally with the ice discharge chute 3. By virtue of this feature, the problems encountered in the packing and transportation of conventional ice making machines can be successfully solved. 
     In the illustrated embodiment, the plate portion defining the opening 6b has an annular portion 6c extending vertically upwardly, as can be seen in FIG. 2. In this connection, the configuration of the inner circumferential surface of this annular portion 6c is preferably conformed to that of the outer circumferential surface 3c of the lower end portion 3b of the ice discharge chute 3. 
     It will be appreciated from the foregoing that according to the invention, as the upwardly concaved recess is provided in the bottom plate of the ice making machinery section and as the ice discharge chute is so disposed that the lower end portion thereof extends within the recess over a distance which is shorter than the depth of the recess, the droplets produced within the ice discharge chute are positively prevented from propagating onto the lower surface of the bottom plate or the ceiling wall of the ice storage chamber and unavoidably forced to drop within the ice storage chamber from the lower end portion of the ice discharge chute. Thus, there is formed on the ceiling wall of the ice storage chamber no trace of the deposition resulting from vaporization of the water droplets. Also, no part of the ice discharge chute projects from the bottom plate upon installation of the ice discharge chute on the ice making machinery section, as a result of which the packing and transportation of the latter can be greatly facilitated. 
     It is felt that the present invention will be understood from the foregoing description and it will be apparent that various changes may be made in the form, construction and arrangement thereof without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred or exemplary embodiment thereof.